1. Field of the Invention
The invention relates to an improved fuel system for an internal combustion engine.
2. Description of the Prior Art
In conventional motor vehicles with gasoline direct injection, the fuel system is embodied so that after the engine is switched off, the fuel pressure continues to be maintained for a period of time. Only through cooling of the engine and fuel system and through leakage into the tank does the pressure in the fuel system slowly decrease. The gradient of the pressure decrease and therefore its duration depend on various boundary conditions and are not possible to calculate.
For reducing emissions when starting the internal combustion engine and for improving starting times and starting quality (dispersion), the pressure in the fuel system, in particular in the high-pressure system, should be as high as possible already prior to the first injection. In that case, it is specifically possible to already reduce the first injection during the compression stroke, thus requiring clearly less fuel, which, in turn, results in reduced emissions. This is referred to as “high-pressure starting.”